Lance Armstrong has been questioned by Italian police as part of the investigation into the intimidation of Filippo Simeoni during last year's Tour de France.

The six-time Tour winner voluntarily travelled to the Tuscan town of Lucca on Wednesday to explain why he chased down Simeoni during stage 18 of the race, even though the Italian was not a threat to his sixth Tour victory.

"I asked for the meeting," Armstrong told the daily Gazzetta dello Sport after leaving the Lucca police station. "The Italian magistrate seemed a smart guy. I think he appreciated my willingness to see him. I simply told him the whole truth."

The magistrate Giuseppe Quattrocchi had formally opened an investigation after Simeoni claimed Armstrong threatened him because he had given evidence in the trial of Dr Michele Ferrari. The doctor was one of Armstrong's key advisers until he was given a suspended one-year sentence for sporting fraud and supplying drugs.

Armstrong had always supported Ferrari, claiming he was an honest man but ended their professional relationship after the guilty verdict.

After giving his version of things Armstrong could still face charges of violenza privata by intimidating a trial witness, but he no longer risks being taken into custody whenever he travels to Italy.

On Tuesday Armstrong hinted he may retire after attempting to win a seventh Tour de France this July and announced an "important" US press conference for April 18.

After Armstrong's trip to Italy Gazzetta dello Sport speculated that Armstrong may have decided to face questioning now so that he can ride the Giro d'Italia next month.

Armstrong has never ridden the three-week race but has always said he would like to do so after living in Italy in the early years of his professional career.

"Armstrong has always said he wants to ride the Giro at least once before retiring," Pier Bergonzi wrote. "If there's chance that it may happen, it had to include resolving his Italian legal problems."

· Next year's Tour de France will start in Strasbourg, with a 7.5km time-trial on July 1.